This invention relates to tetrahydronaphthalenecarboxamide compounds N-substituted by a substituted piperidinylbutyl group, to pharmaceutical compositions containing such compounds, as well as to their uses and processes for their preparation. These compounds antagonize the pharmacological actions of the endogenous neuropeptide tachykinins known as neurokinins, particularly at the neurokinin1 (NK1) and the neurokinin 2 (NK2) receptors. These compounds are useful whenever such antagonism is desired. Thus, such compounds are of value in the treatment of those diseases in which Substance P and Neurokinin A are implicated, for example, in the treatment of asthma, anxiety, depression, emesis, urinary incontinence and related conditions.
The mammalian neurokinins comprise a class of peptide neurotransmitters which are found in the peripheral and central nervous systems. The three principal neurokinins are Substance P (SP), Neurokinin A (NKA) and Neurokinin B (NKB).
There are also N-terminally extended forms of at least NKA. At least three receptor types are known for the three principal neurokinins. Based upon their relative selectivities favoring the neurokinin agonists SP, NKA and NKB, the receptors are classified as neurokinin 1 (NK1), neurokinin 2 (NK2) and neurokinin 3 (NK3) receptors, respectively. In the periphery, SP and NKA are localized in C-afferent sensory neurons, which neurons are characterized by non-myelinated nerve endings known as C-fibers, and are released by selective depolarization of these neurons, or selective stimulation of the C-fibers. C-Fibers are located in the airway epithelium, and the tachykinins are known to cause profound effects which clearly parallel many of the symptoms observed in asthmatics. The effects of release or introduction of tachykinins in mammalian airways include bronchoconstriction, increased microvascular permeability, vasodilation, increased mucus secretion and activation of mast cells. Thus, the tachykinins are implicated in the pathophysiology and airway hyperresponsiveness observed in asthmatics; and blockade of the action of released tachykinins may be useful in the treatment of asthma and related conditions. A cyclopeptide antagonist (FK-224) selective for both NK1 and NK2 receptors has demonstrated clinical efficacy in human patients suffering from asthma and chronic bronchitis. M. Ichinose, et al., Lancet, 1992, 340, 1248.
In particular the N-substituted tetrahydronaphthalenecarboxamide compounds of the present invention show a high degree of NK1 and/or mixed NK1/NK2 receptor antagonist activity. Additionally, by manipulation of the substituents on the naphthalene and piperidine rings of the formula (I), the ratio of activity at the NK1 and NK2 receptors can be modified as desired, affording compounds that are predominantly active at NK1 receptors or affording compounds with a balanced activity and, as such, are particularly useful when combined antagonism of both receptors is desired. In particular, the compounds of the present invention also possess a high degree of NK1 and/or mixed NK1/NK2 antagonism upon oral administration.
Accordingly the present invention provides the compounds of the formula (I): 
wherein:
R is hydrogen, hydroxy, C1-6alkoxy, C1-6alkanoyloxy, C1-6alkanoyl, C1-6alkoxycarbonyl, C1-6alkanoylamino, C1-6alkyl, carbamoyl, C1-6alkylcarbamoyl or di-C1-6alkylcarbamoyl;
R1 is a phenyl group substituted in the ortho position by C1-6alkylthio, C1-6alkyl-sulfinyl, C1-6alkylsulfonyl, trifluoromethylthio, trifluoromethylsulfinyl, C1-6alkane-sulfonamido, C1-6alkanoyl, C1-6alkoxycarbonyl, succinamido, carbamoyl, C1-6alkyl-carbamoyl, di-C1-6alkylcarbamoyl, C1-6alkoxy-C1-6alkylcarbamoyl, C1-6alkanoylamino, ureido, C1-6ureido, di-C1-6alkylureido, amino, C1-6alkylamino or di-C1-6alkylamino, which phenyl group optionally may bear further substituents;
or R1 is a group of the formula (1a): 
wherein Z is NH or CH2.
R2 is an optionally substituted 5,6,7,8-tetrahydronaphth-1-yl group and X1 and X2 are independently hydrogen or halo, provided that at least one of X1 or X2 is halo; and pharmaceutically acceptable salts thereof.
Suitable further substituents, which are optional, for R1 when it is an ortho-substituted phenyl ring include C1-6alkylthio for example methylthio or ethylthio; C1-6alkylsulfinyl for example methylsulfinyl, ethylsulfinyl or propoxysulfinyl; C1-6alkylsulfonyl for example methylsulfonyl or ethylsulfonyl; carboxy; C1-6alkoxycarbonyl for example methoxycarbonyl; C1-6alkanoyl for example acetyl or propionyl; nitro; amino; C1-6alkylamino for example methylamino or ethylamino; di-C1-6alkylamino where the alkyl groups may be the same or different, for example dimethylamino; trifluoromethyl; CF3S(O)x wherein x is 0, 1 or 2, for example trifluoromethylthio, trifluoromethylsulfinyl or trifluoromethylsulfonyl; C1-6alkanoylamino for example acetylamino or propionylamino; C1-6alkalkylsulphonamido for example methylsulphonamido; ureido; C1-6alkylureido for example methylureido (MeNHCONHxe2x80x94), di-C1-6alkylureido for example dimethylureido (Mc,NCONHxe2x80x94); carbamoyl; C1-6alkylcarbamoyl for example methylcarbamoyl; di-C1-6alkylcarbamoyl where the alkyl groups may be the same or different, for example dimethylcarbamoyl; and C1-6alkyl for example methyl substituted by any of the hereinabove substituents.
Suitable substituents, which are optional, for the 5,6,7,8-tetrahydronaphth-1-yl group include hydroxy; cyano; nitro; trifluoromethoxy; trifluoromethyl; C1-6alkylsulfonyl for example methylsulphonyl; halo for example chloro, bromo, fluoro or iodo; C1-6alkoxy for example methoxy, ethoxy or propoxy; methylenedioxy (xe2x80x94OCH2Oxe2x80x94), C1-6alkyl for example methyl or ethyl; C2-6alkenyl for example ethenyl, prop-1-enyl or prop-2-enyl; C2-6alkynyl for example ethynyl; carboxy, C1-6alkoxy-carbonyl for example methoxycarbonyl; carbamoyl; C1-6alkylcarbamoyl for example methylcarbamoyl or ethylcarbamoyl; di-C1-6alkylcarbamoyl for example di-methylcarbamoyl; C1-6alkanoyl for example acetyl or propionyl; C1-6alkanoylamino for example acetylamino or propionylamino; aminosulfonyl; and C1-6alkyl for example methyl substituted by any of the hereinabove substituents.
When R1 is a phenyl ring it is ortho-substituted by C1-6alkylthio for example methylthio; C1-6alkylsulfinyl for example methylsulfinyl, ethylsulfinyl or propylsulfinyl; C1-6alkylsulfonyl for example methylsulfonyl or ethylsulfonyl; trifluoromethylthio; trifluoromethylsulfinyl; C1-6alkanesulfonamido for example methanesulfonamido; C1-6alkanoyl for example acetyl or propionyl; C1-6alkoxy-carbonyl for example methoxycarbonyl; succinamido; carbamoyl; C1-6alkylcarbamoyl for example methylcarbamoyl; di-C1-6alkylcarbamoyl for example dimethylcarbamoyl; C1-6alkoxy-C1-6alkylcarbamoyl for example N-methoxy, N-methylcarbamoyl; C1-6alkanoylamino for example acetylamino; ureido, C1-6ureido for example methylureido; di-C1-6alkylureido for example dimethylureido; amino; C1-6alkylamino for example methylamino or ethylamino; or di-C1-6alkylamino for example dimethylamino.
Preferred values for the ortho-substituent are methylsulfinyl, ethylsulfinyl, propylsulfinyl, methylsulfonyl, trifluoromethylthio, trifluoromethylsulfinyl, methanesulfonamido, acetyl, methoxycarbonyl, succinamido, carbamoyl, methylcarbamoyl, dimethylcarbamoyl, N-methoxy, N-methylcarbamoyl, acetylarnino, ureido, methylureido, dimethylureido, amino, methylamino or dimethylamino.
In particular the ortho-substituent is methylsulfinyl, methylsulfonyl, methylureido, dimethylureido, amino, methylamino or dimethylamino. Of these methylsulfinyl is particularly preferred.
Favourably the ortho-substituted phenyl ring is not substituted further or is substituted by up to three optional substituents. In particular the ortho-substituted phenyl ring is not substituted further or is substituted at the 4-position, that is the position para- to the bond with the piperidine ring, so forming a 2, 4-disubstituted phenyl group, preferably a 2-MeSO, 4-substituted phenyl group.
Preferred substituents if present, for the ortho-substituted phenyl ring, are methyl, methoxy, acetyl, acetylamino, methoxycarbonyl, methanesulfonylamino, methyl-sulfinyl, methylsulfonyl, trifluoromethyl, trifluoromethylthio, trifluoromethylsulfinyl, bromo, fluoro, chloro, hydroxy, carbamoyl, methylcarbamoyl, dimethylcarbamoylmethylureido and dimethylureido. In particular these preferred substituents may be at the 4-position of the phenyl ring.
Thus a preferred class of compounds is that wherein R1 is of the formula (Ib): 
wherein R3 is hydrogen, C1-6alkoxy for example methoxy or ethoxy, halo for example bromo, chloro or fluoro, C1-6alkylsulfinyl for example methylsulfinyl or carboxy.
In particular R3 is hydrogen, C1-6alkoxy or halo.
Most particularly R3 is hydrogen, methoxy or fluoro.
In another aspect R1 is a group of the formula (Ia). In one aspect Z is NH so forming a tetrahydropyrimidone ring. In another aspect Z is methylene so forming a tetrahydropyridone ring.
The compounds of the invention have a number of chiral centres. It is preferred that the ortho-methylsulfinyl substituent, if present, has the stereochemistry depicted in formula (Ic): 
Favourably the 5,6,7,8-tetrahydronaphth-1-yl group (Id): 
is unsubstituted or is substituted by up to three substituents. Preferred substituents for the 5,6,7,8-tetrahydronaphth-1-yl group include cyano; nitro; C1-6alkylsulfonyl for example methylsulphonyl; halo for example chloro, bromo, fluoro or iodo; C1-6alkoxy for example methoxy, ethoxy, n-propoxy or isopropoxy; methylenedioxy (xe2x80x94OCH2Oxe2x80x94); C1-6alkyl for example methyl or ethyl; C2-6alkenyl for example prop-2-enyl; C2-6alkynyl for example ethynyl; carboxy, carbamoyl; C1-6alkyl-carbamoyl for example methylcarbamoyl; di-C1-6alkylcarbamoyl for example di-methylcarbamoyl; C1-6alkanoyl for example acetyl; C1-6alkanoylamino for example acetylamino; aminosulfonyl; and cyanoC1-6alkyl for example cyanomethyl.
More preferred substitutents for the 5,6,7,8-tetrahydronaphth-1-yl group are cyano, methoxy, ethoxy, isopropoxy, fluoro, bromo, chloro, iodo, nitro, cyanomethyl, carboxy, carbamoyl, ethynyl, methyl, dimethylcarbamoyl, methylsulfonyl, aminosulfonyl, prop-2-enyl, acetyl and acetylamino.
In particular the 5,6,7,8-tetrahydronaphth-1-yl group may be substituted by up to two substituents selected from cyano, methoxy, fluoro and nitro. A particularly preferred substitution pattern for the 5,6,7,8-tetrahydronaphth-1-yl group is 3-cyano. A further particularly preferred substitution pattern is 3-cyano, 2-methoxy. Another particularly preferred substitution pattern is 2,3-dimethoxy. Another particularly preferred substitution pattern is 3,4-dimethoxy.
The compounds of the present invention possess a number of chiral centres, at xe2x80x94CH(Ph-X1,X2)xe2x80x94, and possibly in the optional substituents (for example the MeSOxe2x80x94substituent) on either (or both) of the phenyl (when R1 is an ortho-substituted phenyl ring) and the tetrahydronaphth-1-yl groups. The present invention covers all isomers, diastereoisomers and mixtures thereof that antagonise NK1 and/or NK2.
The preferred configuration at xe2x80x94CH(Ph-X1,X2)xe2x80x94 is shown in formula (Ie) hereinbelow: 
Favourably X1 and X2 are both chloro. In a preferred aspect Ph-X1,X2 is 3,4-dichlorophenyl.
R is hydrogen; hydroxy; C1-6alkoxy for example methoxy or ethoxy; C1-6alkanoyloxy for example acetyloxy or propionyloxy; C1-6alkanoyl for example acetyl or propionyl; C1-6alkoxycarbonyl for example methoxycarbonyl or ethoxycarbonyl; C1-6alkanoylamino for example acetylamino; C1-6alkyl for example methyl or ethyl; carbamoyl; C1-6alkylcarbamoyl for example methylcarbamoyl or ethylcarbamoyl or di-C1-6alkylcarbamoyl for example dimethylcarbamoyl.
Preferably R is hydrogen, hydroxy, methoxycarbonyl, methylcarbamoyl or dimethylcarbamoyl. More preferably R is hydrogen or hydroxy; most preferably R is hydrogen.
A preferred class of compounds is that of the formula (II): 
wherein R3 is as hereinbefore defined and R4-R6 are selected from hydrogen, cyano, nitro, methoxy and fluoro. In one particular aspect, in the compounds of the formula (II), R3 is hydrogen, methoxy or fluoro, R4 is hydrogen or fluoro, R6 is hydrogen, and R5 is methoxy, cyano or nitro. In another particular aspect, R3 is hydrogen, methoxy or fluoro, R4 and R5 are hydrogen, and R6 is cyano or nitro. In a further particular aspect, R3 is hydrogen, methoxy or fluoro, R4 is methoxy, R6 is hydrogen, and R5 is cyano or nitro.
Particular compounds of this invention are provided as the Examples hereinbelow;
N-[2-(S)-(3,4-dichlorophenyl)-4-[4-[(S)-2-(methylsulfinyl)phenyl]-1-piperidinyl]butyl]-N-methyl-3-cyano-2-methyl-5,6,7,8-tetrahydro-1-naphthamide;
N-[2-(S)-(3,4-dichlorophenyl)-4-[4-[(S)-2-(methylsulfinyl)phenyl]-1 -piperidinyl]butyl]-N-methyl-3-cyano-2-ethyl-5,6,7,8-tetrahydro-1-naphthamide;
N-[2-(S)-(3,4-dichlorophenyl)4-[4-[(S)-2-(methylsulfinyl)phenyl]-1-piperidinyl]butyl]-N-methyl-3-methoxy-2-methyl-5,6,7,8-tetrahydro-1-naphthamide;
N-[2-(S)-(3,4-dichlorophenyl)4-[4-[(S)-2-(methylsulfinyl)phenyl]-1-piperidinyl]butyl]-N-methyl-2-methoxy-3-methyl-5,6,7,8-tetrahydro-1-naphthamide;
N-[2-(S)-(3,4-dichlorophenyl)-4-[4-[(S)-2-(methylsulfinyl)phenyl]-1-piperidinyl]butyl]-N-methylsulfonyl-3-cyano-2-methoxy-5,6,7,8-tetrahydro-1-naphthamide; and
N-(4-[4-(tetrahydro-2-oxo-1(2H)-pyrimidinyl)-4-methylarminocarbonyl)-1-piperidinyl]-2-(3,4-dichlorophenyl)butyl)-N-methyl-3-cyano-2-methoxy-5,6,7,8-tetrahydro-1-naphthamide.
Pharmaceutically acceptable salts of the compounds of the formula (I) include those made with inorganic or organic acids which afford a physiologically acceptable anion, such as with, for example, hydrochloric, hydrobromic, sulfuric, phosphoric, methanesulfonic, sulfamic, para-toluenesulfonic, acetic, citric, lactic, tartaric, malonic, fumaric, ethanesulfonic, benzenesulfonic, cyclohexylsulfamic, salicyclic and quinic acids.
In order to use a compound of the formula (I) or a pharmaceutically acceptable salt thereof for the therapeutic treatment (including prophylactic treatment) of mammals including humans, it is normally formulated in accordance with standard pharmaceutical practice as a pharmaceutical composition.
Therefore in another aspect the present invention provides a pharmaceutical composition which comprises a compound of the formula (I) or a pharmaceutically acceptable salt and pharmaceutically acceptable carrier.
The pharmaceutical compositions of this invention may be administered in standard manner for the disease condition that it is desired to treat, for example by oral, topical, parenteral, buccal, nasal, vaginal or rectal administration or by inhalation or insufflation. For these purposes the compounds of this invention may be formulated by means known in the art into the form of, for example, tablets, capsules, aqueous or oily solutions, suspensions, emulsions, creams, ointments, gels, nasal sprays, suppositories, finely divided powders or aerosols or nebulisers for inhalation, and for parenteral use (including intravenous, intramuscular or infusion) sterile aqueous or oily solutions or suspensions or sterile emulsions.
In addition to the compounds of the present invention the pharmaceutical composition of this invention may also contain, or be co-administered (simultaneously or sequentially) with, one or more pharmacological agents of value in treating one or more disease conditions referred to herein.
The pharmaceutical compositions of this invention will normally be administered to humans so that, for example, a daily dose of 0.01 to 25 mg/kg body weight (and preferably of 0.1 to 5 mg/kg body weight) is received. This daily dose may be given in divided doses as necessary, the precise amount of the compound received and the route of administration depending on the weight, age and sex of the patient being treated and on the particular disease condition being treated according to principles known in the art.
Typically unit dosage forms will contain about 1 mg to 500 mg of a compound of this invention. For example a tablet or capsule for oral administration may conveniently contain up to 250 mg (and typically 5 to 100 mg) of a compound of the formula (I) or a pharmaceutically acceptable salt thereof. In another example, for administration by inhalation, a compound of the formula (I) or a pharmaceutically acceptable salt thereof may be administered in a daily dosage range of 5 to 100 mg, in a single dose or divided into two to four daily doses. In a further example, for administration by intravenous or intramuscular injection or infusion, a sterile solution or suspension containing up to 10% w/w (and typically 5% w/w) of a compound of the formula (I) or a pharmaceutically acceptable salt thereof may be used.
Therefore in a further aspect, the present invention provides a compound of the formula (I) or a pharmaceutically acceptable salt thereof for use in a method of therapeutic treatment of the human or animal body.
In yet a further aspect the present invention provides a method of treating a disease condition wherein antagonism of the NK1 and/or NK2 receptors is beneficial which comprises administering to a warm-blooded animal an effective amount of a compound of the formula (I) or a pharmaceutically acceptable salt thereof. The present invention also provides the use of a compound of the formula (I) or a pharmaceutically acceptable salt thereof in the preparation of a medicament for use in a disease condition wherein antagonism of the NK1 and/or NK2 receptors is beneficial.
The compounds of the formula (I) and their pharmaceutically acceptable salts may be made by processes as described and exemplified herein and by processes similar thereto and by processes known in the chemical art. If not commercially available, starting materials for these processes may be made by procedures which are selected from the chemical art using techniques which are similar or analogous to the synthesis of known compounds.
In another aspect the present invention provides a process for preparing a compound of the formula (I) or a pharmaceutically acceptable salt thereof which process comprises:
a) reacting a compound of the formula (III) with a compound of the formula (IV): 
wherein R, R1, R2, X1 and X2 are as hereinbefore defined; and L and Lxe2x80x2 are groups such that reductive amination of the compounds of the formulae (III) and (IV) forms a Nxe2x80x94C bond; or
b) reacting a compound of the formula (V) with a compound of the formula (VI): 
wherein R, R1, R2, X1 and X2 are as hereinbefore defined; and Lxe2x80x3 is a leaving group; wherein any other functional group is protected, if necessary, and:
i) removing any protecting groups;
ii) optionally forming a pharmaceutically acceptable salt.
Protecting groups may in general be chosen from any of the groups described in the literature or known to the skilled chemist as appropriate for the protection of the group in question, and may be introduced and removed by conventional methods; see for example Protecting Groups in Organic Chemistry; Theodora W. Greene. Methods of removal are chosen so as to effect removal of the protecting group with minimum disturbance of groups elsewhere in the molecule.
It will also be appreciated that certain of the various optional substituents in the compounds of the formula (I) may be introduced by standard aromatic substitution reactions or generated by conventional functional group modifications either prior to or immediately following the processes described hereinabove. The reagents and reaction conditions for such procedures are well known in the chemical art.
Pharmaceutically acceptable salts may be prepared from the corresponding acid in conventional manner. Non-pharmaceutically acceptable salts may be useful as intermediates and as such are another aspect of the present invention.
It is well known in the art how to prepare optically-active forms (for example, by resolution of the racemic form or by synthesis from optically-active starting materials) and how to determine the NK1 and NK2 antagonist properties by the standard tests known in the art and those described hereinafter.
The compounds of the formulae (III) and (IV) are reacted under conditions of reductive amination. Typically in the compounds of the formula (III) L is hydrogen.
Typically in the compounds of the formula (IV) Lxe2x80x2 is an oxo group so forming an aldehyde moiety. The reaction is typically performed at a non-extreme temperature, for example 0-100xc2x0 C., suitably ambient temperature in a substantially inert solvent for example dichloromethane. Typical reducing agents include borohydrides such as sodium cyanoborohydride.
The compounds of the formula (III) are known or made be prepared in conventional manner. The compounds of the formula (IV) may be prepared, for example, by reacting a compound of the formula (VI) with a compound of the formula (VII): 
wherein Lxe2x80x2, X1 and X2 are as hereinbefore defined under conventional acylation conditions.
The compounds of the formulae (V) and (VI) may be reacted under conventional acylation conditions wherein Lxe2x80x3COxe2x80x94R2 is an acid or an activated acid derivative. Such activated acid derivatives are well known in the literature. They may be formed in situ from the acid or they may be prepared, isolated and subsequently reacted. Typically Lxe2x80x3 is chloro thereby forming the acid chloride. Typically the acylation reaction is performed in the presence of a non-nucleophilic base, for example di-isopropylethylamine, in a substantially inert solvent at a non-extreme temperature.
The compounds of the formula (VII) are known or may be prepared in conventional manner. Compounds of the formula (IV) and certain compounds of the formula (VI) are novel and form part of the present invention. In particular the compounds of the formula (VI) wherein the aromatic ring of the 5,6,7,8-tetrahydronaphth-1-yl group is substituted by at least one group selected from cyano, nitro, methoxy and fluoro are novel. For example, a preferred class of novel compounds is of the formula (VIII): 
wherein Lxe2x80x3 is as hereinbefore defined; preferably Lxe2x80x3 is hydrogen or a leaving group such as chloro; R7 is hydrogen or methoxy and R8 is hydrogen, methoxy or cyano with the proviso that R7 and R8 are not both hydrogen when Lxe2x80x3 is hydrogen.
In another aspect the present invention provides a compound of the formulae (IX): 
wherein X1, X2 and Lxe2x80x2 are as hereinbefore defined, R7 is hydrogen or methoxy and R8 is hydrogen, methoxy or cyano.
The following biological test methods, data and Examples serve to illustrate and further describe the invention.
The utility of a compound of the invention or a pharmaceutically acceptable salt thereof (hereinafter, collectively referred to as a xe2x80x9cCompoundxe2x80x9d) may be demonstrated by standard tests and clinical studies, including those disclosed in the publications described below.
The ability of a Compound of the invention to antagonize the binding of SP at the NK1 receptor may be demonstrated using an assay using the human NK1 receptor expressed in Mouse Erythroleukemia (MEL) cells. The human NK1 receptor was isolated and characterized as described in: B. Hopkins, et al. xe2x80x9cIsolation and characterization of the human lung NK1 receptor cDNAxe2x80x9d Biochem. Biophys. Res. Comm., 1991, 180, 1110-1117; and the NK1 receptor was expressed in Mouse Erythroleukemia (MEL) cells using a procedure similar to that described in Test B below.
The ability of a Compound of the invention to antagonize the binding of NKA at the NK2 receptor may be demonstrated using an assay using the human NK2 receptor expressed in Mouse Erythroleukermia (MEL) cells, as described in: Aharony, D., et al. xe2x80x9cIsolation and Pharmacological Characterization of a Hampster Neurokinin A Receptor CDNAxe2x80x9d Molecular Pharinacology, 1994, 45, 9-19.
The selectivity of a Compound for binding at the NK1 and the NK2 receptors may be shown by determining its binding at other receptors using standard assays, for example, one using a tritiated derivative of NKB in a tissue preparation selective for NK3 receptors. In general, the Compounds of the invention which were tested demonstrated statistically significant binding activity in Test A and Test B with a Ki of 1 microM or much less typically being measured.
The ability of a Compound of the invention to antagonize the action of the agonist Ac-[Arg6, Sar9, Met(O2)11] Substance P (6-11), ASMSP, in a pulmonary tissue may be demonstrated as follows.
Male New Zealand white rabbits are euthanized via i.v. injection into an ear vein with 60 mg/kg Nembutal (50 mg/mL). Preceding the Nembutal into the vein is Heparin (1000 units/mL) at 0.0025 ml/kg for anticoagulant purposes. The chest cavity is opened from the top of the rib cage to the sternum and the heart, lungs and part of the trachea are removed. The pulmonary arteries are isolated from the rest of the tissues and cut in half to serve as pairs.
The segments are suspended between stainless steel stirrups, so as not to remove any of the endothelium, and placed in water-jacketed (37xc2x0 C.) tissue baths containing physiological salt solution of the following composition (mM): NaCl, 118.0; KCl, 4.7; CaCl2, 1.8; MgCl2, 0.54; NaH2PO4, 1.0; NaHCO3, 25.0; glucose, 11.0; indomethacin, 0.005(to inhibit cyclooxygenase); and dl-Propranolol, 0.00l(to block xcex2 receptors); gassed continuously with 95% O2-5% CO2. Responses are measured on a Grass polygraph via Grass FT-03 transducers and the electrical signals (data) acquired using a Mi2 software/hardware system for subsequent conversion to measures of relaxation.
Initial tension placed on each tissue is 2 grams, which is maintained throughout the 1.0 hour equilibration period. Tissues are washed with the physiological salt solution at 15 minute intervals. At the 30 and 45 minute wash the following treatments are added: 1xc3x9710xe2x88x926M Thiorphan (to block E.C.3.4.24.11), 3xc3x9710xe2x88x928M (S)-N-[2-(3,4-Dichlorophenyl)-4-[4-oxoperhydropyrimidin-1-yl)piperidino]butyl]-N-methylbenzamide (to block NK2 receptors), and the given concentration of the Compound being tested. At the end of the 1.0 hour equilibration, 1xc3x9710xe2x88x926M L-Phenylephrine hydrochloride is added for 1.0 hour. At the end of the 1.0 hour, a dose relaxation curve to ASMSP is done. Each tissue is treated as a individual and is considered finished when it fails to relax further for 2 consecutive doses. When this section of the protocol is complete, 1xc3x9710xe2x88x923M Papaverine is added for maximum relaxation.
For non-competitive antagonists, the percent inhibition of relaxation is determined at a given concentration of the antagonist. Percent inhibition is determined when a tested Compound produces a statistically significant (p less than 0.05) reduction of the total relaxation which is calculated using the total relaxation as a percent of the control value. Potencies of competitive Compounds are determined by calculating the apparent dissociation constants (KB) for each concentration tested using the standard equation:
KB=[antagonist]/(dose ratio xe2x88x921)
where dose ratio antilog[(agonist xe2x88x92log molar EC50 without Compound)xe2x88x92(xe2x88x92log molar EC50 with Compound)]. The KB values may be converted to the negative logarithms and expressed as xe2x88x92log molar KB (i.e. PKB). For this evaluation, complete concentration-response curves for agonist obtained in the absence and presence of the Compound tested using paired pulmonary artery rings. The potency of the agonist is determined at 50% of its own maximum relaxation in each curve. The EC50 values are converted to negative logarithms and expressed as xe2x88x92log molar EC50.
The ability of a Compound of the invention to antagonize the action of the agonist [xcex2-ala8] NKA (4-10), BANK, in a pulmonary tissue may be demonstrated as follows. Male New Zealand white rabbits are euthanized via i.v. injection into an ear vein with 60 mg/kg Nembutal (50 mg/mL). Preceding the Nembutal into the vein is Heparin (1000 units/mL) at 0.0025 mL/kg for anticoagulant purposes. The chest cavity is opened from the top of the rib cage to the stemum and a small incision is made into the heart so that the left and right pulmonary arteries can be cannulated with polyethylene tubing (PE260 and PE190 respectively). The pulmonary arteries are isolated from the rest of the tissues, then rubbed over an intimal surface to remove the endothelium, and cut in half to serve as pairs. The segments are suspended between stainless steel stirrups and placed in water-jacketed (37.0xc2x0 C.) tissue baths containing physiological salt solution of the following composition (mM): NaCl, 118.0; KCl, 4.7; CaCl2, 1.8; MgCl2, 0.54; NaH2PO4, 1.0; NaHCO3, 25.0; glucose, 11.0; and indomethacin, 0.005 (to inhibit cyclooxygenase); gassed continuously with 95% O2-5% CO2. Responses are measured on a Grass polygraph via Grass FT-03 transducers and the electrical signals (data) acquired using a Mi2 software/hardware system for subsequent conversion to measures of contraction.
Initial tension placed on each tissue is 2 grams, which is maintained throughout the 45 minute equilibration period. Tissues are washed with the physiological salt solution at 15 minute intervals. After the 45 minute equilibration period, 3xc3x9710xe2x88x922M KCl is given for 60 minutes to test the viability of the tissues. The tissues are then washed extensively for 30 minutes. The concentration of the Compound being tested is then added for 30 minutes. At the end of the 30 minutes, a cumulative dose response curve to BANK is performed. Each tissue is treated as a individual and is considered finished when it fails to contract further for 2 consecutive doses. When this section of the protocol is complete, 3xc3x9710xe2x88x922M BaCl2 is added for maximum contraction.
For non-competitive antagonists, the percent inhibition of contraction is determined at a given concentration of the antagonist Percent inhibition is determined when a tested Compound produces a statistically significant (p less than 0.05) reduction of the total contraction which is calculated using the total contraction as a percent of the control value. Potencies of competitive Compounds are determined by calculating the apparent dissociation constants (KB) for each concentration tested using the standard equation:
KB=[antagonist]/(dose ratio xe2x88x921)
where dose ratio=antilog[(agonist xe2x88x92log molar EC50 without Compound)xe2x88x92(xe2x88x92log molar EC50 with Compound)]. The KB values may be converted to the negative logarithms and expressed as xe2x88x92log molar KB (i.e. pKB). For this evaluation, complete concentration-response curves for agonist obtained in the absence and presence of the Compound tested using paired pulmonary artery rings. The potency of the agonist is determined at 50% of its own maximum contraction in each curve. The EC50 values are converted to negative logarithms and expressed as xe2x88x92log molar EC50.
The activity of a compound as an antagonist of NK1 and/or NK2 receptors also may be demonstrated in vivo in laboratory animals as described in: Buckner et al. xe2x80x9cDifferential Blockade by Tachykinin NK1 and NK2 Receptor Antagonists of Bronchoconstriction Induced by Direct-Acting Agonists and the Indirect-Acting Mimetics Capsaicin, Serotonin and 2-Methyl-Serotonin in the Anesthetized Guinea Pig.xe2x80x9d J. Pharm. Exp. Ther., 1993, Vol 267(3), pp 1168-1175. The assay is carried out as follows.
Compounds are tested in anesthetized guinea pigs pretreated with i.v. indomethacin (10 mg/kg, 20 min.), propranolol (0.5 mg/kg, 15 min.), and thiorphan (10 mg/kg, 10 min).
Antagonists or vehicle are administered i.v. and orally, 30 and 120 minutes prior to increasing concentrations of agonist, respectively. The agonists used in these studies are ASMSP (Ac-[Arg6,Sar9,Met(O2)11]-SP(6-11)) and BANK (xcex2-ala-8 NKA4-10).
Administered i.v., ASMSP is selective for NK1 receptors, and BANK is selective for NK2 receptors. Maximum response is defined as zero conductance (GL, 1/Rp). ED50 values are calculated (the dose of agonist resulting in a reduction of GL to 50% of baseline), and converted to the negative logarithm (xe2x88x92logED50). The ED50 values, obtained in the presence (P) and absence (A) of antagonist, are used to calculate a Dose Ratio (P/A), an expression of potency. Data are expressed as meanxc2x1SEM and statistical differences were determined using ANOVA/Tukey-Kramer and Student""s t-test , with p less than 0.05 considered statistically significant.
Compounds of the present invention exhibit marked activity in the foregoing tests and are considered useful for the treatment of those diseases in which the NK1 and/or NK2 receptor is implicated, for example, in the treatment of asthma and related conditions.
Results of testing of representative compounds of the present invention by the above methods are presented in the Table I
Clinical studies to demonstrate the efficacy of a Compound of the invention may be carried out using standard methods. For example, the ability of a Compound to prevent or treat the symptoms of asthma or asthma-like conditions may be demonstrated using a challenge of inhaled cold air or allergen and evaluation by standard pulmonary measurements such as, for example, FEV1 (forced expiratory volume in one second) and FVC (forced vital capacity), analyzed by standard methods of statistical analysis.
It will be appreciated that the implications of a Compound""s activity in the above described Tests is not limited to asthma, but rather, that the Tests provide evidence of general antagonism of both SP and NKA. SP and NKA have been implicated in the pathology of numerous diseases including: rheumatoid arthritis, Alzheimer""s disease, cancer, schizophrenia, oedema, allergic rhinitis, inflammation, pain, gastrointestinal-hypermotility, gastric asthma, gastroesphageal reflux, anxiety, emesis, Huntington""s Disease, psychoses including depression, hypertension, migraine, bladder hypermotility and urticaria.
Accordingly, one feature of the invention is the use of a compound of formula I or a pharmaceutically acceptable salt thereof in the treatment of a disease in a human or other mammal in need thereof in which SP or NKA is implicated and antagonism of its action is desired.
Asthma is characterized by both chronic inflammation and hyperresponsiveness of the airways. The NK1 receptor is known to mediate inflammation and mucus hypersecretion in airways; and the NK2 receptor is involved in the control of the tone of bronchial smooth muscle. Thus, agents capable of antagonizing the actions of SP and NKA, at the NK1 and NK2 receptors, respectively, are capable of reducing both the chronic inflammation and the airway hyperresponsiveness which are symptomatic of asthma. It has been suggested that an antagonist having mixed affinity for NK1 and NK2 could be therapeutically superior to a receptor selective antagonist. C. M. Maggi xe2x80x9cTachykinin Receptors and Airway Pathophysiologyxe2x80x9d Eur. Respir. J., 1993, 6, 735-742 at 739. Also, it has been suggested that a synergistic effect against bronchoconstriction may result from the simultaneous application of an NK1 antagonist and an NK2 antagonist. D. M. Foulon, et al. xe2x80x9cNK1 and NK2 Receptors Mediated Tachykinin and Resiniferatoxin-induced Bronchospasm in Guinea Pigsxe2x80x9d American Review of Respiratory Disease, 1993, 148, 915-921. Accordingly, another feature of the invention is the use of a compound of formula I or a pharmaceutically acceptable salt thereof in the treatment of asthma in a human or other mammal in need thereof. There is a possible role for Substance P antagonists in the treatment of depression. Accordingly another feature of the invention is the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the treatment of depression in a human or other mammal in need thereof.
Because of the range of effects attributable to the actions of SP and NKA, compounds which are capable of blocking their actions may also be useful as tools for further evaluating the biological actions of other neurotransmitters in the Tachykinin family. As a result, another feature of the invention is provided by the use of a compound of Formula I or a salt thereof as a pharmacological standard for the development and standardization of new disease models or assays for use in developing new therapeutic agents for treating diseases in which SP or NKA are implicated or for assays for their diagnosis.
The invention is illustrated by the following non-limiting examples, in which, unless stated otherwise:
(i) operations were carried out at room or ambient temperature, that is, at a temperature in the range of 18-25xc2x0 C.;
(ii) organic solutions were dried over anhydrous magnesium sulfate; evaporation of solvent was carried out using a rotary evaporator under reduced pressure (600-4000 pascals; 4.5-30 mm Hg) with a bath temperature of up to 60xc2x0 C.;
(iii) melting points are uncorrected;
(iv) final products had satisfactory proton nuclear magnetic resonance (NMR) spectra; (v) Mass spectra (MS) were run using an automated system with atmospheric pressure chemical ionization (APCI). Where indicated, the following alternative methods of ionization were used; a) desorption chemical ionization (CI) using methane reagent gas and a direct exposure probe; b) electron impact (EI) or c) fast atom bombardment(FAB). Generally, only spectra where parent masses are observed are reported.
Abbreviations: CO, carbon monoxide; DCM; methylene chloride, DMF; N;N-dimethylformamide, DMSO; dimethyl sulfoxide, Et2O; diethyl ether, EtOAc; ethyl acetate, h; hour(s), min; minutes, NMR; nuclear magnetic resonance, psi; pounds per square inch, THF; tetrahydrofuran.
Standard acylation refers to the typical procedure in which an acid chloride (1-1.2 equivalents) is added to a stirred solution of an amine (1-1.2 equivalents) and triethylamine (2 equivalents) in DCM. After 1-16 h the reaction is optionally concentrated, dissolved in DCM, and washed with saturated sodium bicarbonate and then purified by chromatography.
Standard reductive amination refers to the typical procedure in which a solution of an amine (1-1.2 equivalents), an aldehyde (1-1.2 equivalents) and acetic acid (2 equivalents) are stirred in methanol for 5 to 60 minutes before adding NaBH3CN (1.7 equivalents). After 1-16 h the reaction is optionally concentrated, dissolved in DCM, and washed with saturated sodium bicarbonate and then purified by chromatography.
Final compounds were converted to the citrate salt. The free base was combined with citric acid (1.0 equivalents) in methanol, concentrated under reduced pressure and dried under vacuum (25-50xc2x0 C.).